Socket for bi-post lamps



May 1, 1962 J. L. BONANNO SOCKET FOR BI-POST LAMPS Filed Aug. 9, 1957 III 2 Sheets-Sheet 1 INVENTOR Jwzm/Aflwmwm 9m fla/id M ATTORNEY5 y 1, 1962 J. L. BONANNO 3,032,738

SOCKET FOR BI-POST LAMPS Filed Aug. 9, 1957 2 Sheets-Sheet 2 ATTOR EYS 3,032,738 SOCKET FOR BI-POST LAMPS Joseph L. Bonanno, South Orange, N.J., assignor to The Lionel Corporation, New York, N.Y., a corporation of New York Filed Aug. 9, 1957, Ser. No. 677,402 Claims. (Cl. 339-155) This invention relates to improvements in detachable electric contact assemblies, and has particular relation to a novel socket structure for receiving and holding the terminals pins of miniature electrical components, such as small electric light bulbs, plugs, or the like.

The invention is especially intended to afford ready attachment of miniature electrical components such as miniature bulbs into an electric circuit. While such an application may find wide and varied use, it is especially suited, for example, to use in small scale models requiring lights, lamps and other electrical devices sized according to the miniature scale. Such scale models may be in the nature of electric trains, miniature scale railroads, miniature villages, and the like. In such miniature models it is desired to reproduce all of the elements in scale for the sake of authenticity. In such models requiring electric lighting or other electrical features, the uniformity of scale is invariably interrupted when it is necessary to provide detachable contact or terminal elements; the conventional sockets, binding posts, and other circuit elements being of a relatively large size. For example, in small scale models including a lighting system, the uniformity of scale is impaired by the use of the conventional small light bulbs which have standardized metal bases for reception in standardized sockets of either the screw or bayonet type. Since the construction of these standardized lamp bases and sockets requires them to be relatively large and bulky as compared to the miniature scale of the model, the authenticity of the model is retarded by the use of lights.

It is an object of the present invention therefore to provide a circuit connection assembly in which an element in the nature of a socket is adapted to receive and retain an electrical component to be inserted into the circuit; the socket element being made of a size small enough to correspond to the scale of miniature models. In addition, the electrical component can also be made in the same scale, with a pair of projecting terminals pins for insertion into the socket.

By way of example, a light bulb and socket assembly made in accordance with the invention includes a light bulb having a pair of terminal pins instead of the usual metal screw or bayonet base, and the socket includes a pair of contact springs for making electrical contact with the bulb terminal pins and also physically holding the latter.

Another object of the invention is the provision of circuit coupling means of the character described in which the socket portion includes a relatively few inexpensive parts, so that it is extremely economical in manufacture. Further, the electrical component to be inserted into the circuit, for example a light bulb, can be made of a smaller size than normally, and need not be provided with the usual metal contact base, so that it is also economical in manufacture.

A further object of the invention is the provision of a socket assembly of the character described in which a minimum of coil spring contacts are required to permit wiring of a plurality of electrical components in series, in parallel, or in parallel series, thereby eliminating separate circuit wiring in the socket.

Additional objects and advantages of the invention will become apparent in the course of the following specification when taken in connection with the accompanying drawings, in which:

Patented May 1, 1962 FIG. 1 is an exploded perspective view of a lamp housing containing a pair of light bulbs and a socket for receiving the bulbs, made in accordance with the invention;

FIG. 2 is a front elevational view of the socket shown in FIG. 1 with the cover removed to reveal the interior thereof;

FIG. 3 is a central vertical section through the assembled lamp housing, with the bulbs omitted, the section being taken substantially along line 3-3 of FIG. 2;

FIG. 4 is a horizontal section through. the assembled lamp housing as viewed along line 44 of FIG. 2;

FIG. 5 is a vertical section through the assembled lamp housing taken along line 55 of FIG. 4 and showing the bulbs in mounted position; and

FIG. 6 is a section taken along line 5-6 of FIGS. 2 and 5.

Referring in detail to FIGS. 1 to 3 of the drawings, there is shown a lamp housing of the type used in miniature models, for example, in small scale railroads, or the like. The particular housing which is illustrated by way of example, is the form of a railroad signal light, but it is to be understood that the socket assemblies of the invention are intended for use in all applications where lights or other electrical components are required for miniature models, or for use in other structures which require small light bulbs, sockets, or electrical elements.

The lamp housing comprises a hollow casing 19 which acts as an enclosure for a pair of lamp bulbs 11, and which is attachable to a lamp socket 12 to complete the assembled housing, the socket 12 being dimensioned to serve as the rear wall of the housing.

The bulbs 11 are identical and are made in a form which differs from that of the usual small size incandescent bulbs. Each bulb 11 has a glass envelope 13 with which a glass base 14 is integrally molded, a pair of terminal pins 15 and 16 being molded and rigidly set in said base 14. The terminal pins 15 and 16 are connected respectively to the ends of the bulb filament 17. The envelope 13 and molded base 14 are of a smaller size than the usual pilot bulbs or flashlight bulbs which are customarily used for this purpose, the small size being made possible because of the elimination of the conventional metal lamp bases and their replacement by the terminal pins 15 and 16.

The socket 12 has a body made of insulating material such as molded plastic, and has an open front end communicating with an enlarged central cavity 18. The cavity 18 is bordered by a forwardly-projecting flange 19 extending around the periphery thereof and sized to receive the end of the casing 10 when the lamp housing is as sembled.

A pair of separator elements 20 and 21, molded in tegrally with the rear wall of the socket 12, divide the cavity 18 into a pair of spaced, longitudinally-disposed contact chambers 22 and 23. A coiled compression spring 24 made of electrically conductive metal is seated in the contact chamber 22. The spring 24 in its untensioned state has a normal length greater than the length of the contact chamber 22 so that it must be slightly compressed to be inserted within the contact chamber 22. This slight compression serves to maintain spring 24 within the contact chamber 22 and it also enables the spring 24 to make good electrical contact with and to physically retain the terminal pins of the bulbs 11, as will be presently described.

A partition wall 25 formed integrally with the socket rear wall and located centrally in the contact chamber 23, divides the contact chamber 23 into two half sections. A pair of coiled compression springs 26 and 27 are inserted into the contact chamber 23 on either side of the partition wall 25, the latter electrically insulating the springs 26 and 27 from each other. At the same time,

the spring 24 is insulated from the springs 26 and 27 by the separator elements and 21. The springs 26 and 27 are made longer than the half-sections of contact chamber 23 so that they are compressed when inserted into said half-sections.

A cover plate 28 of insulating material such as fibre board, is sized to close off the front open surface of the socket 12. The cover plate 28 has a pair of spaced apertures 29 and 30, each of which is of identical shape. The aperture 29 has an enlarged central portion 29a and a pair of narrow end portions 2% and 29:: as shown in FIG. 1. The aperture has similar portions 3%, 30b and sec. Each aperture 29 and 30 is sized to receive the end of one of the bulb bases 14 with the terminal pins 15 and 16 projecting through narrow end portions of the apertures. The end portions 29b, 29c and 30b, 30c, thus serve as socket inlet openings for the terminal pins. The glass base 14 of each bulb 11 is molded or otherwise formed with a protuberance 14a between the terminal pins 15 and 16, the protuberance 14a being sized to fit snugly within the enlarged central portion 29a or 30a of one of the apertures 29 and 30.

The cover plate 28 also has an aperture 31 through which the shank of a screw 32 may pass. The screw shank also extends through a bore 33 in the rear wall of socket 12 and is held in position by a nut 34, whereby the cover plate 28 is fixedly mounted on the socket 12, as shown in FIG. 3. In the mounted position of the cover plate 28, the apertures 29 and 30 are so positioned that the narrow end portions 29b and 290 of aperture 29 register respectively with the springs 24 and 26, while the narrow end portions 301) and 30c of aperture 30 register respectively with the springs 24 and 27. When the base end of a bulb 11 inserted in the aperture 29, in the positions shown in FIGS. 1 and 2, the terminal pin 15 engages and is gripped by the spring 24, while the terminal pin 16 is engaged and gripped by the spring 26. Similarly, when a bulb 11 is inserted in the aperture 30, its terminal pins 15 and 16 are engaged and gripped by the respective springs 24 and 27.

The terminal pins of the inserted bulbs 11 move into contact with the contact springs in a direction perpendicular to the longitudinal axis of the springs and sub stantially parallel to the plane of the spring coils. Since each of the springs 24, 26 and 27 is compressed within its respective contact chamber, as previously described, each terminal pin slides between adjacent coil turns of its corresponding spring and presses apart said adjacent turns, as is clearly shown in FIGS. 2 and 5. These adjacent turns which are spread apart against the tension of the spring, thus make firm electrical contact with the inserted terminal pin. In addition, the spread-apart turns press the terminal pin tightly therebetween and thereby frictionally hold and retain the bulb 11 in inserted position so that no further physical mount for the bulb is required.

Insulated lead wires 35 and 36 are connected to the respective contact springs 26 and 27, the wires 35 and 36 being intended for connection to the terminals of an electric power source, such as an electric train transformer. In the arrangement shown in FIG. 2, it will be appreciated that the two bulbs 11 are wired in series, the electrical current passing from wire 35, for example, through contact spring 26, across the filament of the upper bulb 11, through spring 24 and across the filament of the lower bulb 11, and thence through contact spring 27 and wire 36 to complete the series circuit.

It will be appreciated, of course, that the contact spring assembly also easily lends itself to parallel circuit wiring, and that more than two bulbs or other electrical components can be incorporated in a fixture.

To complete the assembly of the lamp housing, means are provided for removably attaching the casing 10 to the assembled socket 12. While any suitable means may serve for this purpose, an economical and effective attachment is afforded by the spring clip 50 shown in the drawings. The spring clip 50 is of U-shaped, its side arms terminating in inwardly bent portions 50a. The side arms of the spring clip 54} are received and held within channels 51 formed in ribs 52 which are integral with or secured to the inner side wall surfaces of the casing 10. A split rivet 53 extending through the casing front wall embraces and holds the end arm of the clip 59, thereby securely mounting the clip within the casing 10. The casing 10 is brought into registering mounted position upon socket 12 by inserting the socket flange 19 within the open end of said casing. The projecting end of the sprin clip Ed is then received in channels 54 on the sides of socket 12, and the inwardly bent portions 56a embrace the socket rear wall surface, releasably coupling the socket 12 and casing 19 under spring tension.

The casing 10 is provided with a pair of front window openings 55 which register with the contained bulbs 11 for allowing passage of the light emitted by said bulbs exteriorly of the casing. The window openings may be bordered by visors or hoods 56 in simulation of a railroad signal device. The socket 12 may be provided with projecting ears 57 which receive mounting pins 58 for at tachment of the lamp housing to a support, standard or the like.

An important feature of the invention is the ability of the contact springs to grasp and retain the bulb terminal pins so that no further mounting means for the bulb are required. For this purpose of holding the bulb, it may be desired to employ springs made of metal having the proper degree of springiness, but inadequate electrical conductivity. In this instance, an auxiliary electrical conductor may be associated with the contact spring to augment the conductivity of said spring.

While a preferred embodiment of the invention has been shown and described herein, it is obvious that numerous additions, changes and omissions may be made without departing from the spirit and scope of the invention.

I claim:

1. A socket for use with two or more electrical components having terminal pins comprising a hollow body portion, wall means defining three coil spring retaining chambers within said body portion, an elongated coil spring held in substantial compression within each of said retaining chambers with at least a portion of the first and second springs laterally aligned in parallel relation with the third spring and the first and second springs axially aligned with each other, the adjacent turns respectively of said first and third springs constructed and arranged for resiliently engaging the terminal pins of a first electrical component at a tangential relation to said turns of the springs, and the second and third springs constructed and arranged for resiliently engaging the terminal pins of a second electrical component at a tangential relation to said turns of the springs, said terminal pins each passing through spaced openings in said wall means and having the axis of each pin spaced from the axis of the adjacent spring by a distance substantially equal to the radius of the spring, said terminal pins being generally perpendicular to the longitudinal axes of said springs, and means connecting the first and second springs to difierent potentials of a power source.

2. A socket for use with electrical components having terminal pins comprising a hollow body portion, wall means defining three coil spring retaining chambers Within said body portion, an elongated coil spring held in substantial compression Within each of said retaining chambers with at least a portion of the first and second springs being laterally aligned in parallel relation with the third spring and the first and second springs axially aligned with each other, means connecting the first and second springs respectively to separate terminals of a power source, an insulating cover plate for said body portion, said plate having at least one terminal pin receiving opening in alignment respectively with the first and third springs and at least one terminal pin receiving opening in alignment respectively with the second and third springs, each of said terminal pins having its axis thereof spaced from the longitudinal axis of the adjacent spring by a distance substantially equal to the radius of the spring, each opening allowing entry of the terminal pins between adjacent turns of said springs at a tangential relation to said turns of the springs in a direction substantially perpendicular to the longitudinal axes of said springs.

3. A socket for electrical components receiving pairs of terminal pins according to claim 2, including a substantially cup shaped lamp cover having apertures in the closed end portion thereof and being open at said opposite end and being adapted to fit upon said hollow body portion about said open end, and securing means to hold said cover to said body portion.

4. Apparatus according to claim 3, wherein said securing means comprises a U-shaped spring clip mounted within the lamp cover, said clip having a pair of bent end portions projecting beyond the open end of said cover, said bent portions adapted to engage the outer surface of the body portion for releasably coupling said cover to said body portion.

5. A combination lamp and socket assembly comprising a hollow body portion, wall means defining three coil spring retaining chambers within said body portion, an elongated coil spring held in substantial compression within each of said retaining chambers with at least a portion of the first and second springs being laterally aligned in parallel relation with the third spring and the first and second springs axially aligned with each other,

means connecting the first and second springs to separate terminals of a power source, an insulating cover plate for said body portion, said plate lying in a plane substantially parallel to the plane defined by the longitudinal axes of said springs, said plate having an electrical component receiving opening in alignment respectively with the first and third springs and an electrical component receiving opening in alignment respectively with the second and third springs, and a pair of lamps each having terminal pins extending through said plate openings into resilient engagement with adjacent turns of said springs at a tangential relation to the turns thereof, each of said terminal pins having its axis thereof spaced from the longitudinal axis of the adjacent spring by the distance equal to the radius of said adjacent spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,669,784 Scofield May 15, 1928 1,776,859 Johnston Sept. 30, 1930 1,958,895 Bayliss May 22, 1934 1,990,687 Godare Feb. 12, 1935 2,063,110 McArdle Dec. 8, 1936 2,219,326 Meuer Oct. 29, 1940 2,267,080 Clayton Dec. 23, 1941 2,465,100 Johnson Mar. 22, 1949 2,599,361 Beal June 3, 1952 2,682,650 Zion June 29, 1954 2,732,534 Giel Ian. 24, 1956 2,790,153 Arson Apr. 23, 1957 2,899,668 Gribben Aug. 11, 1959 

